digikam does not open evolution "new message"

When evolution is not running everything works fine: Start digikam, select a picture, do "email image". Then I get the new mail window from evolution to write some text and send the mail. However, when evolution is already running, I do not get that email window. Looks like evolution is ignoring digikam.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: digikam 2:1.9.0-1ubuntu1
ProcVersionSignature: Ubuntu 2.6.38-10.46-generic 2.6.38.7
Uname: Linux 2.6.38-10-generic i686
NonfreeKernelModules: nvidia
Architecture: i386
Date: Sat Jul 23 15:07:16 2011
ProcEnviron:
 LANGUAGE=de_DE:en
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: digikam
UpgradeStatus: Upgraded to natty on 2011-06-11 (41 days ago)